The specific objective of this cooperative research project is to evaluate clinical effectiveness of chemotherapeutic agents in the treatment of patients with advanced prostatic cancer. There are now Protocols available for both those patients who have failed to respond to existing methods of therapy and those who are currently stable and not showing any progression of their disease. Patients from the several cooperating institutions will be randomized to various treatment groups under the Protocols being operated at that time. By using similar patients from several institutions the project will be able to evaluate potential agents in the treatment of prostatic carcinoma more rapidly than any single institution alone. Four Protocols have now been completed. Protocol 100: 5-Fluorouracil and Cyclophosphamide compared to Standard treatment and Protocol 200: Estracyt and Streptozotocin compared to Standard treatment, Protocol 300: Procarbazine and DTIC compared with Cyclophosphamide, and Protocol 400: Estracyt in combination with Leo 1031 compared to Leo 1031 alone. Protocols currently in operation are Protocol 500 comparing Cyclophosphamide plus Estracyt to Cyclophosphamide plus Diethylstilbestrol to Diethylstilbestrol or hormonal manipulation alone in patients who have not been previously treated for prostatic carcinoma; Protocol 600 which uses these same agents in patients with newly discovered disease. Protocol 700 is comparing Methyl CCNU with Hydroxyurea and Cyclophosphamide. Protocol 800 is comparing Estracyt and Vincristine with Estracyt and Vincristine in combination. Protocols mentioned above and new Protocols being brought out as old ones are filled are available from any of the participating institutions. Basic decisions to evaluate other chemotherapeutic agents will be made by the members of the National Prostatic Cancer Project in council with the National Cancer Institute.